provided that the LNV interactions of the other RHN species do not become efficient before sphaleron freeze-out.\(12\endcsname \)In the remainder of this paper, though, we will mostly focus on RHN mass spectra with \(M_{1,2,3} \gtrsim 10^5\,\textrm {GeV}\) , assuming that all three RHN species reach chemical equilibrium at one point or other, in which case the bound in Eq. (REF ) turns into \(M_1 \gtrsim T_{y_e} \sim 10^5\,\textrm {GeV}\) .

Wash-in leptogenesis thus successfully operates at RHN masses as low as a few 100 TeV, which is four orders of magnitude below the typical mass range of standard thermal leptogenesis, \(M_i \gtrsim 10^9\,\textrm {GeV}\)  [1]}, [2]}.
Moreover, it does not require small mass splittings in the RHN mass spectrum as in the case of resonant leptogenesis [3]}, [4]}.
A hierarchical spectrum as in our benchmark scenario is indeed a perfectly viable option.
